Coupler for coupling two containers stacked on top of one another, especially aboard a ship

ABSTRACT

The invention relates to a coupler for coupling two containers stacked on top of one another, especially aboard a ship, which has an upper coupling projection ( 10 ) engaging in a bottom corner fitting of the upper container and a lower coupling projection ( 11 ) engaging in a top corner fitting of the lower container, which coupling projection has in longitudinal direction of the containers a lateral coupling lug ( 22 ) and a vertical back wall ( 21 ), which is mounted on the side of the lower coupling projection ( 11 ) facing away from the coupling lug ( 22 ) in such a way that the space (b) between a free edge ( 25 ) of the coupling lug ( 22 ) and the back wall ( 21 ) is smaller than or equal to the width of an upper slotted hole in the top corner fitting. To securely couple two containers stacked on top of one another even when outrightly exposed to tractive forces, the invention-based coupler is characterized in that the lower coupling projection ( 11 ) in the back wall ( 21 ) has a recess ( 26 ) which extends in slot-like manner across the entire length of the lower coupling projection ( 11 ).

The invention relates to a coupler for coupling two containers stackedon top of one another, especially aboard a ship, which has an uppercoupling projection engaging in a bottom corner fitting of the uppercontainer and a lower coupling projection engaging in a top cornerfitting of the lower container, which coupling projection has inlongitudinal direction of the containers a lateral coupling lug and avertical back wall, which is mounted on the side of the lower couplingprojection facing away from the coupling lug in such a way that thespace between a free edge of the coupling lug and the back wall issmaller than or equal to the width of an upper slotted hole in the topcorner fitting.

Such a coupler has been disclosed in DE 102 38 895 A1.

Because of the fact that containers allow for rapid cargo handling, theyhave gained great acceptance for transporting goods. Therefore, constantefforts are made to improve the rigging process of the containers aboarda ship. In addition to safety issues, it has also been attempted toaccelerate the handling of the containers in the ports, in order toreduce the waiting times of the ships. In particular, this applies tothe containers transported on deck of ships. At first, they were securedmanually using twistlocks, which had to be manually applied when loadingthe ship with containers, as well as unloading the containers. This wasnot only very time-consuming, but required also the presence ofstevedores on deck while loading the containers, forcing them to workunder suspended loads. Moreover, in unfavorable weather conditions, thesurface of the containers on which the stevedores have to walk is veryslippery. This involved considerable dangers for the stevedores,resulting in the fact that in the 1990s it was prohibited during theperiod of loading a ship that stevedores stayed in the bay area that wasloaded with containers.

A first step toward increasing the safety of the stevedores andaccelerating container handling was the use of semiautomatic twistlocks(SAT). Semiautomatic twistlocks couple automatically when the uppercontainer is placed on the lower container, so that the containersstacked on top of one another are permanently coupled together. However,to unload the containers, the semiautomatic twistlocks have to bemanually opened by the stevedores. This process is safe for thestevedores because they can open all twistlocks of the containers to beunloaded as soon as the ship is in the port, and they can leave the shipbefore the containers are lifted from the ship. Consequently, thestevedores no longer have to stay under suspended loads. However, themanual process of uncoupling the twistlocks remains very time-consuming.

The above-mentioned DE 102 38 895 A1 introduces a fully automatictwistlock (FAT), which fully automatically couples the containers whenan upper container is placed on a lower container and fullyautomatically decouples the containers when they are unloaded. Thestowage personnel is only required to insert at the dock the fullyautomatic twistlocks into the bottom corner fittings of the uppercontainer before the container is lifted aboard the ship, or to removeat the dock the twistlocks after the container is lifted off the ship.

A lateral coupling lug makes sure that the fully automatic twistlockaccording to DE 102 38 895 A1 securely couples the containers stacked ontop of one another during the maritime transport. This fully automatictwistlock is based on the knowledge that pitching motions of the shiphardly result in any vertical acceleration of the containers, whichexposes the containers to hardly any or no lift-off forces. It is truethat considerable vertical acceleration occurs when the ship is rolling.However, in this case, compressive forces on the one lateral side(pressure side) occur between two containers stacked on top of oneanother while on the other lateral side tractive forces (tensile side)occur. Because of the design of the fully automatic twistlock, thetwistlocks mounted on the pressure side prevent the two containersstacked on top of one another from shifting horizontally against eachother. This ensures that the coupling lugs of the twistlocks mounted onthe tensile side are prevented from uncoupling. However, when at theport the upper container is lifted by a crane, tractive forces areapplied to all four twistlocks, making it possible that they areuncoupled.

However, it is still feared that under certain conditions in specificstowage spaces, for example, in a front or rear bay, tractive forcescould occur on all four twistlocks and result in undesired uncoupling.To prevent this from happening, it has been proposed using fullyautomatic twistlocks which have two coupling lugs situated opposite fromone another (DE 20 2004 017 252 U1). FIG. 3 of this document shows sucha fully automatic twistlock, in which both coupling lugs are arranged ondifferent levels. This results in a “Z-motion” both during the coupling,as well as the uncoupling process, which is considered to be ofdisadvantage, because the containers could be jammed or caught duringthe loading or unloading process.

Based on these facts, the invention proposes to further develop theabove-mentioned coupler in such a way that it securely couples twocontainers stacked on top of one another even when outrightly exposed totractive forces and that it prevents “Z-motions” from occurring duringthe coupling and uncoupling process.

To solve this problem, the invention-based coupler is characterized inthat the lower coupling projection in the back wall has a recess whichextends in slot-like manner across the entire length of the lowercoupling projection.

Therefore, the invention-based coupler is basically designed in the formof a fully automatic twistlock according to DE 102 38 895 A1. However, aslot-like recess is provided in the back wall of the twistlock. As aresult, the “Z-motion” which occurred during the coupling and uncouplingprocess is eliminated. If, despite all provisions, the coupling lug onthe tensile side should slide out of the associated corner fitting,i.e., be released behind the edge of the slotted hole of said cornerfitting, the upper container would slip on the lower containerhorizontally in a direction that is opposite to the direction in whichthe coupling lug points, i.e., in the direction of the recess. As aresult, the edge of the upper slotted hole that is opposite of thecoupling lug engages with the recess, so that the coupler is notcompletely uncoupled. The upper container remains coupled with the lowercontainer. In addition, the invention-based coupler has specificemergency operating features.

By means of the recess an additional lug is formed on the side facingaway from the coupling lug. This lug should have a shoulder that isinclined to the outside. In this way, it can be prevented that the lowercoupling projection gets caught at the slotted hole of the cornerfitting, if the edge of the slotted hole should accidentally engage inthe recess during the process of unloading the container. For thispurpose, the inclined collar does not have to be as flat as the shoulderof the coupling lug. As a result, the angle of the shoulder to a backwall of the lower coupling lug can be larger than the angle of theshoulder of the coupling lug to a front wall. For manufacturing reasons,it is especially preferred when the shoulder of the lug is aligned withan inside surface of a grip recess in the lower coupling projection.Usually, couplers are made of steel casting and the aligned shoulderwould make it easier to produce the casting mold.

According to a further development of the invention, on a side that isopposite of the lug, i.e., on a side facing the upper couplingprojection, the recess is restricted by an inclined insertion surface.If the recess is applied in the above-mentioned manner or, during theprocess of coupling the coupler with the top edge fitting of the lowercontainer, the edge of the slotted hole would accidentally get into therecess (which could happen because of wind pressure or because thecontainer starts swinging on the crane), the inclined insertion surfacewould ensure that the coupler attains (again) its coupled position.

Subsequently, the invention is described in more detail by means of anembodiment depicted in the drawing. It is shown:

FIG. 1 a front view of the coupler having the characteristics of theinvention, and

FIG. 2 a lateral view of the coupler shown in FIG. 1.

The depicted coupler has an upper coupling projection 10 and a lowercoupling projection 11. A lock 12 has been arranged between the couplingprojections 10, 11, which also forms a parting plane between twocontainers stacked on top of one another (not shown). The bottom side ofthe lock 12 is attached to the upper side of the top corner fitting ofthe lower container, while the bottom side of the of the bottom cornerfitting of the upper container is standing on the top side of the lock12. However, according to the invention, provision has also been made todesign in well-known manner the lock 12 merely in the form of aprotruding wedge-like bulge, which then engages in a groove formed bybevels at the slotted holes of the corner fittings. As a result, thecorner fittings of the containers are standing directly on top of oneanother.

Above the lock 12, the upper coupling projection 10 has a shaft 13,which has a head 14 on the side facing away from the lock 12. FIG. 1clearly shows that the head 14 protrudes on both sides beyond the shaft13, thus forming locking projections 15 and 16.

The lower coupling projection 11 also connects to the lock 12 by meansof a shaft 17. On the one side, the shaft 17 has a front wall 18 whichextends vertically to the lock 12. On the side that is located oppositeof the front wall 18 the shaft 17 has an inclined insertion surface 19which crosses over to a bevel 20 on the end facing the lock 12. Thisbevel 20 correspond with a bevel at the slotted hole of the cornerfitting and is attached to the bevel when the coupler is coupled.Therefore, the bevel 20 could also be considered to be part of the lock12, especially when the lock 12 is designed in the form of a bulge, asdescribed above.

At the end facing away from the lock 12, the inclined insertion surface19 crosses over in arch-like manner to a back wall 21, which is alsoarranged vertically to the lock 12.

Furthermore, the lower coupling projection 11 has a coupling lug 22,which is located opposite of the back wall 21. The coupling lug 22 isarranged laterally in relation to a longitudinal axis of the twocontainers to be coupled. On its upper surface, the coupling lug 22 hasa shoulder 23 that is inclined to the outside. Furthermore, an insertionpin 24 has been arranged on the lower side of the coupling lug 22 ist ander Unterseite der Kupplungsnase 22. The width b of the couplingluggsnase 22, i.e., a space between a free edge 25 of the coupling lug22 and the back wall 21, is maximally as wide as the width of theslotted hole into which the lower coupling projection 11 engages.

In this respect, at least the lower coupling projection 11 correspondsbasically to the fully automatic twistlock according to DE 102 38 895A1. In contrast to the fully automatic twistlock according to DE 102 38895 A1, the coupler according to the present embodiment has a slot-likerecess 26 in the back wall 21. The recess 26 extends across the entirelength of the lower coupling projection 11 or the back wall 21 and has abase 27 extending parallel to the back wall 21. On the side facing theupper coupling projection 10 or lock 12, the groove 26 is restricted byan inclined insertion surface 28, and on the side located opposite ofthe inclined insertion surface 28, i.e., the side facing away from theupper coupling projection 10 or lock 12, it is restricted by an inclinedshoulder 29. Therefore, the groove 26 has a trapezoid shape, wherein theangle of the inclined insertion surface 28 and the angle of the inclinedshoulder 29 do not have to be equal in relation to the back wall 21.Instead, FIG. 1 clearly shows that the inclined insertion surface 28 issteeper than the inclined shoulder 29, with an angle of approximately135°, while the inclined shoulder 29 has an angle α₂₉ of approximately110° in relation to the back wall 21.

Furthermore, the inclined shoulder 29 is not as steep as the inclinedshoulder 23 of the coupling lug 22. In the present embodiment, theinclined shoulder 29 restricting the recess 26 is aligned with a lowerinside surface 30 of a grip recess 31, which is shown in FIG. 1 as acovered edge with a dotted line. In general it can be stated that anangle α₂₃ of the inclined shoulder 23 of the coupling lug 22 in relationto the vertical line, i.e., to the front wall 18, is larger than orequal to the angle α₂₉ of the inclined shoulder 29 restricting therecess 26 in relation to the back wall 21.

By means of the recess 26 in the lower coupling projection 11 a furtherlug 32 is formed, the upper side of which forms the inclined shoulder 29restricting the recess 29. If required, with this further lug 32, thecoupler can hook behind the edge at the upper slotted hole of theassociated corner fitting.

The locking projections 15, 16 of the head 14 of the upper couplingprojection 10 have lower supporting surfaces 33 or 34 facing the lock12. At the same time, the supporting surface 34 of locking projection16, which is located above locking lug 22, is arranged closer to theupper side of the lock 12 (parting plane between containers stacked ontop of one another), and thus lower than the supporting surface 33 ofthe opposite locking projection 15.

BEZUGSZEICHENLIST

-   10 upper coupling projection-   11 lower coupling projection-   12 lock-   13 shaft-   14 head-   15 locking projection-   16 locking projection-   17 shaft-   18 front wall-   19 inclined insertion surface-   20 bevel-   21 back wall-   22 coupling lug-   23 bevel (the locking lug 22)-   24 insertion pin-   25 edge-   26 recess-   27 Grund-   28 base-   29 bevel (the recess 26)-   30 inside surface-   31 grip recess-   32 further lug-   33 supporting surface-   34 supporting surface

1. A coupler for coupling two containers stacked on top of one another,especially aboard a ship, which has an upper coupling projection (10)engaging in a bottom corner fitting of the upper container and a lowercoupling projection (11) engaging in a top corner fitting of the lowercontainer, which coupling projection has a shaft (17) with a front wall(18), a lateral coupling lug (22) arranged in longitudinal direction ofthe containers, and a vertical back wall (21), which is mounted on theside of the lower coupling projection (11) facing away from the couplinglug (22) in such a way that the space (b) between a free edge (25) ofthe coupling lug (22) and the back wall (21) is smaller than or equal tothe width of an upper slotted hole in the top corner fitting, whereinthe shaft (17) on the side opposite of the front wall (18) has aninclined insertion surface (19), characterized in that the lowercoupling projection (11) in the back wall (21) has a recess (26) whichextends in slot-like manner across the entire length of the lowercoupling projection (11).
 2. A coupler according to claim 1,characterized in that a further lug (32) has been arranged on a side ofthe recess (26) facing away from the upper coupling projection (10),which further lug has an upper shoulder (29) that is inclined to theoutside.
 3. A coupling projection according to claim 2, characterized inthat the angle (α₂₉) of the shoulder (29) of the lug (32) in relation tothe back wall (21) is larger than or equal to an angle (α₂₃) of aninclined upper shoulder (23) of the coupling lug (22) in relation to afront wall (18) of the lower coupling projection (11).
 4. A coupleraccording to claim 2, characterized in that the shoulder (29) of the lug(32) is aligned with an inside surface (30) of a grip recess (31) in thelower coupling projection (11).
 5. A coupler according to claim 1,characterized in that the recess (26) on a side facing the uppercoupling projection (11) is restricted by an inclined insertion surface(28).
 6. A coupler according to claim 3, characterized in that theshoulder (29) of the lug (32) is aligned with an inside surface (30) ofa grip recess (31) in the lower coupling projection (11).
 7. A coupleraccording to claim 2, characterized in that the recess (26) on a sidefacing the upper coupling projection (11) is restricted by an inclinedinsertion surface (28).
 8. A coupler according to claim 3, characterizedin that the recess (26) on a side facing the upper coupling projection(11) is restricted by an inclined insertion surface (28).
 9. A coupleraccording to claim 4, characterized in that the recess (26) on a sidefacing the upper coupling projection (11) is restricted by an inclinedinsertion surface (28).
 10. A coupler according to claim 6,characterized in that the recess (26) on a side facing the uppercoupling projection (11) is restricted by an inclined insertion surface(28).